This invention relates generally to the field of magneto-optic disc drive data storage devices, and more particularly, but not by way of limitation, to an improved head assembly for a magneto-optical disc drive data storage device which includes features for preventing media asperities from degrading the performance of the read/write function.
Magneto-optical disc drive data storage devices, or magneto-optical drives, are well known in the industry. Such devices utilize a combination of electromagnetic and optical light technologies to store and retrieve data on the surface of appropriately designed plastic discs.
Evolutionary advances in the disc media and read/write heads have lead to the present generation of magneto-optical disc drives which are capable of large amounts of data on one side of a single disc. In order to achieve such data capacities, the magneto-optical transducers used to record and retrieve data are incorporated in self-acting hydrodynamic head assemblies that fly above the discs on a thin layer of air dragged along by the spinning disc. Head assemblies of the current generation typically fly at heights above the disc that bring the operative component of the magneto-optical transducer to within approximately 4 microinches (0.000004 inch) of the media surface.
Current manufacturing technology for the disc media produce discs that include both undulations on the size order of the head assembly and defects (tall single asperities). While the head assembly is capable of controlled flight over media undulations, a media asperity, while generally small enough to not affect the flying characteristics of the head assembly, can cause degradation of the magneto-optical head/disc interface, resulting in corruption of data storage and retrieval operations or, at worst, fatal failure of the disc drive.
Media asperities cause head/disc interface degradation because, when a media asperity passes under the magneto-optical transducer, small pieces of the media surface are broken off and can accumulate on the operative portion of the transducer. If enough of this media debris accumulates on the transducer, the optical performance of the transducer is negatively impacted.
While media manufacturing technology continues to advance, providing media with improved surface characteristics, a need still exists for apparatus that will prevent media asperities from degrading the performance of the magneto-optical head.
The present invention is a magneto-optical head assembly that includes waffle-like burnishing features incorporated into the air bearing surfaces of the head assembly. The magneto-optical mesa, or operative feature of the magneto-optical head assembly is configured such that the burnishing features are closer to the disc surface than the mesa. During operation, media asperities are contacted by the burnishing features rather than the mesa, and media debris generated by contact with the burnishing features is accumulated within the burnishing features, preventing degradation of read/write performance. Various methods for fabricating the magneto-optical head assembly and alternative configurations of the burnishing features are discussed.
It is an object of the invention to provide a magneto-optical head assembly for use with magneto-optical disc recording media.
It is another object of the invention to provide a magneto-optical head assembly that can operate on disc media with tall single asperities without suffering degradation of magneto-optical performance.
It is another object of the invention to provide a magneto-optical head assembly that includes features for burnishing asperities on the disc surface and accumulating any generated debris in the burnishing features.
It is another object of the invention to provide a magneto-optical head assembly which can be manufactured in a simple and economical manner.
The manner in which the present invention achieves these objects, as well as other features and benefits of the invention, can best be understood by a review of the following Detailed Description of the Invention, when read in conjunction with and examination of the accompanying drawings.